{
  "bibcode": "2014GCN.17078....1T",
  "body": "M. Tanga (MPE Garching), D. A. Kann (TLS Tautenburg), and J. Greiner (MPE\nGarching) report on behalf of the GROND team:\n\nWe observed the field of GRB 141121A (Swift trigger 619182; A. Y. Lien et\nal., GCN 17075) simultaneously in g'r'i'z'JHK with GROND (Greiner et al.\n2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at ESO La Silla\nObservatory (Chile).\n\nObservations started at 05:52 UT on November 21, 2014, 2.02 hours after\nthe GRB trigger. They were performed at an average seeing of 1\".4 and at\nan average airmass of 2.3.\n\nWithin the XRT error circle reported by Lien et al., we detect a bright\nsource in all bands. This source is not detected in the SDSS, therefore we\nconsider it to be the afterglow of GRB 141121A. The source lies at:\n\nRA (J2000) = 08:10:40.62\nDec. (J2000) = +22:13:01.8\n\nwith an error of 0\".3 in each coordinate.\n\nBased on total exposures of 7.7 minutes in g'r'i'z' and 8.0 minutes in\nJHK, at a midtime of 2.34 hrs after the burst, we measure the following\npreliminary magnitudes (AB magnitude system):\n\ng' = 20.0 +/- 0.1 mag,\nr' = 19.8 +/- 0.1 mag,\ni' = 19.6 +/- 0.1 mag,\nz' = 19.4 +/- 0.1 mag,\nJ = 19.4 +/- 0.2 mag, and\nH = 19.2 +/- 0.2 mag.\n\nThe magnitudes are calibrated against SDSS and 2MASS field stars and are\nnot corrected for the Galactic foreground extinction corresponding to a\nreddening of E_(B-V)= 0.05 in the direction of the burst (Schlegel et al.\n1998).",
  "circularId": 17078,
  "createdOn": 1416554106000,
  "email": "kann@tls-tautenburg.de",
  "subject": "GRB 141121A: GROND Afterglow candidate",
  "submitter": "Alexander Kann at TLS Tautenburg  <kann@tls-tautenburg.de>",
  "eventId": "GRB 141121A"
}